rhashtable: Fix walker list corruption
authorHerbert Xu <herbert@gondor.apana.org.au>
Wed, 16 Dec 2015 08:45:54 +0000 (16:45 +0800)
committerDavid S. Miller <davem@davemloft.net>
Wed, 16 Dec 2015 16:13:14 +0000 (11:13 -0500)
commitc6ff5268293ef98e48a99597e765ffc417e39fa5
tree383abd638c072a92aab2e874870607b1147b8797
parent3a324606bbabfc30084ce9d08169910773ba9a92
rhashtable: Fix walker list corruption

The commit ba7c95ea3870fe7b847466d39a049ab6f156aa2c ("rhashtable:
Fix sleeping inside RCU critical section in walk_stop") introduced
a new spinlock for the walker list.  However, it did not convert
all existing users of the list over to the new spin lock.  Some
continued to use the old mutext for this purpose.  This obviously
led to corruption of the list.

The fix is to use the spin lock everywhere where we touch the list.

This also allows us to do rcu_rad_lock before we take the lock in
rhashtable_walk_start.  With the old mutex this would've deadlocked
but it's safe with the new spin lock.

Fixes: ba7c95ea3870 ("rhashtable: Fix sleeping inside RCU...")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
lib/rhashtable.c